The four context strategies — Write / Select / Compress / Isolate

A practical framework for managing what enters the context window. Write stores
information outside the window (scratchpads, runtime state, external notes).
Select pulls in only what is relevant right now (retrieval, tool selection).
Compress reduces what is already present (summarisation, pruning, recency
ordering). Isolate separates concerns so one task's context does not pollute
another's — for example using a sub-agent or the agent's own runtime state object as
a boundary. These four verbs give students a vocabulary for diagnosing and fixing
context problems for the rest of the course.